Get single char from console immediately

Question

Is it possible to get each char from STDIN once it is provided (without waiting for return key)?

stdin is not necessarily (or even usually) a tty. – William Pursell Nov 09 '11 at 22:43 — William Pursell, Nov 09 '11 at 22:43

J-_-L · Answer 1 · 2016-03-21T16:40:15.783

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This is possible with Ruby 1.9.3's new getch method:

require 'io/console'
input = STDIN.getch

Docs (Core): http://ruby-doc.org/core-2.3.0/IO.html#class-IO-label-io-2Fconsole

Docs (Lib): http://ruby-doc.org/stdlib-2.3.0/libdoc/io/console/rdoc/IO.html#method-i-getch

Source: https://github.com/ruby/ruby/tree/trunk/ext/io/console

edited Mar 21 '16 at 16:40

answered Nov 09 '11 at 22:29

J-_-L

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A pointer to the docs would be helpful. – Misha Moroshko Jan 25 '12 at 10:51
Thanks, shout out to you in this answer here: http://stackoverflow.com/a/20081966/8047 – Dan Rosenstark Nov 19 '13 at 21:06
Don't forget to add `exit if input=="\u0018" or input=="\u0003"` if you are in a loop – Paul Verschoor May 30 '20 at 09:51

score 4 · Accepted Answer · answered Nov 09 '11 at 22:54

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Yes, there are numerous ways to do this, and besides gems you can directly manipulate with terminfo through gems for termios, ncurses or stty program.

tty_param = `stty -g`
system 'stty raw'

a = IO.read '/dev/stdin', 1

system "stty #{tty_param}"

print a

answered Nov 09 '11 at 22:54

tensai_cirno

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This should be deprecated in favor of @J-_-L 's answer. – notapatch Aug 25 '15 at 15:21

score 2 · Answer 3 · edited May 28 '21 at 06:02

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Use the Highline gem:

require "highline/system_extensions"  # gem install highline
include HighLine::SystemExtensions

print "Enter one character:  "
char = get_character
puts char.chr

from JEG II's blog.

edited May 28 '21 at 06:02

fractious

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answered Nov 09 '11 at 22:28

Phrogz

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Get single char from console immediately

3 Answers3

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